Start the game by buying a Doran's blade and 1 Health Potion. Get a Tiamat on your first back and then build Black Cleaver on your next one. After that you will want to complete your Titanic Hydra. Somewhere along the line if you have extra gold you can get boots. Depending on the enemy team's comp you will either get Mercury's Treads or Ninja Tabi. You can either get Enchantment: Alacrity or Enchantment: Distortion depending on your preference. Personally, I like Distortion so that I am able to make more plays with my Teleport. After you get those three items you will get Sterak's Gage as it will allow you to dive into the enemies' team without taking to much burst damage. Next, I recommend that you get Warmog's Armor because it will give you more sustain in team fights. Finally, get a guardian's angel for your last item because not only does it give you both armor and magic resist, it also gives you some an extra life so that even if the enemy team uses all their' ults on you, you will not be completely out of the team fight. You will still be able to deal damage and be an efficient front line Bruiser/ Tank. After you've completed you 6 items you can either get an Elixir of Iron or an Elixir of Wrath depending on how much damage your team already has. If your team already produces a lot of damage then you might want to settle for the Elixir of Iron. However if your team lacks the damage that is necessary for late game, then you might just buy the Elixir of Wrath. Overall, Renekton if a lane bully and a good late game champion. Good Luck and Have Fun!